Update Math::BigInt::FastCalc to CPAN version 0.25

Update Math::BigInt::FastCalc to CPAN version 0.25

# New Ticket Created by  (Peter J. Acklam)
# Please include the string:  [perl #84982]
# in the subject line of all future correspondence about this issue.
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=84982 >

Remove _new() from XS code and use _new() in Math::BigInt::Calc
instead. The XS _new() doesn't handle integers that are too large to
be represented exactly as floating point numbers, but small enough
to be represented as 64 bit integers. E.g., even with 64 bit integer
support, applying _num() to 18446744073709551615 (= 2**64-1) gives
1.84467440737096e+19, not 18446744073709551615. The XS _new() also
returns nan, not inf, when it overflows. This closes RT #63335 and
RT #49569.

Signed-off-by: Chris 'BinGOs' Williams <chris@bingosnet.co.uk>